1. Field of the Invention
The present invention relates to a method of controlling communications among electronic devices in a system where electronic controls with different types of communication protocols coexist, a construction machine using this control method, and an electronic circuit of such a construction machine.
2. Description of the Related Art
Recently, the number of electronic devices mounted in construction machines is increasing, and a communication procedure (protocol) used among the electronic devices has come to be used in multiple numbers.
And, a conventional construction machine is separately provided with a communication line for each of the communication procedures (hereafter, it is called, “communication protocols”) to deal with the plurality of communication protocols. Such a conventional construction machine is described in, for example, Japanese Patent Publication No. 8-28911.
Thus, the number of communication lines is increased and the system structure is complex because the communication lines are provided for the multiple communication protocols respectively. And, when a new electronic device using another communication protocol is added, major modifications are required.
According to the above structure, the communication line having a different communication protocol is used to backup a communication failure of one of the communication lines.
But, a processing procedure to use the line of another communication protocol is complex, it is difficult to give redundancy, and safety is low.
As described above, the conventional device had the communication lines for the respective communication protocols, increasing the number of communication lines and having a complex system structure. And, addition of a new electronic device using another communication protocol had a disadvantage that major modifications were required.
In the conventional structure where another different communication protocol is used in order to backup a communication failure of one line, the processing procedure to use the line of another communication protocol is complex. As a result, there is a problem that it is difficult to give redundancy, and safety is low.